refactor(plex): move content_libs down into the query layer

The browse scope is a pure DB query with no request state, but it lived in
routes/plex/_shared.py. E24's Home surface needs the same scope from a domain
package, and a domain package importing from routes/ inverts the one-way
dependency CLAUDE.md draws.

Moved to app/plex/query.py and renamed to content_libs (public — it is a domain
helper now). Swept all five call sites and both tests in one go rather than
leaving a re-export shim: the canonical-patterns table already names the
routes.admin re-export as the anti-pattern.

backend/app/plex/query.py

@@ -8,8 +8,9 @@ from datetime import datetime, timedelta, timezone
 
 from sqlalchemy import and_, case, func, or_, select, type_coerce
 from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Session
 
-from app.models import PlexItem
+from app.models import PlexItem, PlexLibrary
 
 TS_CONFIG = "public.unaccent_simple"
 
@@ -342,3 +343,26 @@ def apply_show_state_filter(query, tot, wat, inp, show: str):
     if show == "unwatched":
         return query.where(wat == 0, inp == 0)
     return query
+
+
+def content_libs(db: Session) -> tuple[list[int], list[int]]:
+    """The BROWSABLE content libraries, partitioned into (movie_lib_ids, show_lib_ids) — the single
+    source of the browse scope. Excludes HU overlay libraries (`overlay_of` set): those are never
+    browsed on their own, they only lend their Hungarian metadata to the EN twin's rows (E5 S5).
+
+    Lives here, in the query layer, rather than in `routes/plex/_shared.py` where it started: E24's
+    Home surface needs the same scope, and a domain package importing from `routes/` would invert the
+    one-way dependency CLAUDE.md draws. It never touched request state, so nothing was lost by the
+    move."""
+    libs = (
+        db.execute(
+            select(PlexLibrary).where(
+                PlexLibrary.enabled.is_(True), PlexLibrary.overlay_of.is_(None)
+            )
+        )
+        .scalars()
+        .all()
+    )
+    movie_lib_ids = [lb.id for lb in libs if lb.kind == "movie"]
+    show_lib_ids = [lb.id for lb in libs if lb.kind == "show"]
+    return movie_lib_ids, show_lib_ids

backend/app/routes/plex/_shared.py

@@ -3,13 +3,9 @@
 import logging
 
 from fastapi import HTTPException
-from sqlalchemy import select
 from sqlalchemy.orm import Session
 
-from app.models import (
-    PlexItem,
-    PlexLibrary,
-)
+from app.models import PlexItem
 from app.plex.lookups import by_rating_key
 
 log = logging.getLogger("siftlode.plex")
@@ -25,21 +21,3 @@ def item_or_404(db: Session, rating_key: str) -> PlexItem:
 def _norm_lang(lang: str | None) -> str:
     """The overlay has an EN base + an optional HU twin; anything other than `hu` serves EN."""
     return "hu" if lang == "hu" else "en"
-
-
-def _content_libs(db: Session) -> tuple[list[int], list[int]]:
-    """The BROWSABLE content libraries, partitioned into (movie_lib_ids, show_lib_ids) — the single
-    source of the browse scope. Excludes HU overlay libraries (`overlay_of` set): those are never
-    browsed on their own, they only lend their Hungarian metadata to the EN twin's rows (E5 S5)."""
-    libs = (
-        db.execute(
-            select(PlexLibrary).where(
-                PlexLibrary.enabled.is_(True), PlexLibrary.overlay_of.is_(None)
-            )
-        )
-        .scalars()
-        .all()
-    )
-    movie_lib_ids = [lb.id for lb in libs if lb.kind == "movie"]
-    show_lib_ids = [lb.id for lb in libs if lb.kind == "show"]
-    return movie_lib_ids, show_lib_ids

backend/app/routes/plex/browse.py

@@ -34,6 +34,7 @@ from app.plex.query import (
     apply_meta_filters,
     apply_movie_state_filter,
     apply_show_state_filter,
+    content_libs,
     field_recheck,
     genres_col,
     meta_filter_conds,
@@ -47,7 +48,7 @@ from app.plex.query import (
     vector_col,
     vector_match,
 )
-from app.routes.plex._shared import _content_libs, _norm_lang
+from app.routes.plex._shared import _norm_lang
 from app.utils import to_tsquery_str
 
 router = APIRouter(prefix="/api/plex", tags=["plex"])
@@ -109,7 +110,7 @@ def unified_library(
     offset = max(0, offset)
     lang = _norm_lang(lang)
     p = f.as_dict()
-    movie_lib_ids, show_lib_ids = _content_libs(db)
+    movie_lib_ids, show_lib_ids = content_libs(db)
     want_movies = scope in ("movie", "both") and bool(movie_lib_ids)
     want_shows = scope in ("show", "both") and bool(show_lib_ids)
 
@@ -328,7 +329,7 @@ def facets(
         "duration_min": None,
         "duration_max": None,
     }
-    all_movie_ids, all_show_ids = _content_libs(db)
+    all_movie_ids, all_show_ids = content_libs(db)
     movie_ids = all_movie_ids if scope in ("movie", "both") else []
     show_ids = all_show_ids if scope in ("show", "both") else []
     if not movie_ids and not show_ids:

backend/app/routes/plex/collections.py

@@ -19,8 +19,7 @@ from app.plex import sync as plex_sync
 from app.plex.cards import movie_card, show_card
 from app.plex.client import PlexClient, PlexError, PlexNotConfigured
 from app.plex.lookups import by_rating_key
-from app.plex.query import like_escape, runtime_by_key, top_art_keys
-from app.routes.plex._shared import _content_libs
+from app.plex.query import content_libs, like_escape, runtime_by_key, top_art_keys
 
 # The most-restrictive → least ordering used to pick a collection's effective content rating from its
 # members (Plex shows one cert on the collection; we don't store it, so derive it).
@@ -128,7 +127,7 @@ def collections(
     # members (a collection lives in one library, so exactly one side has art) — a show collection would
     # otherwise render blank; the collection's own poster is the next fallback, then the colour hash.
     # Runtime is movie-only (shows have no single duration).
-    movie_ids, show_ids = _content_libs(db)
+    movie_ids, show_ids = content_libs(db)
     keys = [c.rating_key for c in rows]
     art_m = top_art_keys(db, PlexItem, movie_ids, PlexItem.collection_keys, keys, per=2)
     art_s = top_art_keys(db, PlexShow, show_ids, PlexShow.collection_keys, keys, per=2)

backend/app/routes/plex/people.py

@@ -19,8 +19,7 @@ from app.models import (
 from app.plex import rollup
 from app.plex import tmdb as plex_tmdb
 from app.plex.cards import movie_card, show_card
-from app.plex.query import split_csv
-from app.routes.plex._shared import _content_libs
+from app.plex.query import content_libs, split_csv
 
 router = APIRouter(prefix="/api/plex", tags=["plex"])
 log = logging.getLogger("siftlode.plex")
@@ -71,7 +70,7 @@ def people_cards(
     wanted = split_csv(names)[:16]
     if not wanted:
         return {"people": []}
-    movie_lib_ids, show_lib_ids = _content_libs(db)
+    movie_lib_ids, show_lib_ids = content_libs(db)
     want_movies = scope in ("movie", "both") and bool(movie_lib_ids)
     want_shows = scope in ("show", "both") and bool(show_lib_ids)
     photos = {
@@ -185,7 +184,7 @@ def person_detail(
         and _should_schedule_enrich(person.id)
     ):
         background_tasks.add_task(_enrich_person_bg, person.id)
-    movie_lib_ids, show_lib_ids = _content_libs(db)
+    movie_lib_ids, show_lib_ids = content_libs(db)
 
     movies: list[dict] = []
     if movie_lib_ids: